Synthesis and antimicrobial applications of 5,5′-ethylenebis[5-methyl-3-(3-triethoxysilylpropyl)hydantoin]

Physical Contact-Triggered In Situ Reactivation of Antibacterial Hydrogels

In situ reactivation of hydrogels remains a long-standing key challenge in chemistry and materials science. Herein, we first report an ultraconvenient in situ renewable antibacterial hydrogel prepared via a facile physical contact-triggered strategy based on an ultrafast chlorine transfer pathway. We discover that the as-proposed hydrogel with a programmable 3D network cross-linked by noncovalent bonds and physical interactions can serve as a smart platform for selective active chlorine transfer at the hydrogel/hydrogel interface. Systematic experiments and density functional theory prove that the N-halamine glycopolymers integrated into the hydrogel system work as a specific renewable biocide, permitting the final hydrogel to be recharged in situ within 1 min under ambient conditions. Due to its strength and durability, pathogen specificity, and biocompatibility, coupled with its rapid in situ reactivation, this antibacterial hydrogel holds great potential for in vivo biomedical use and circulating water disinfection. We envision this proposed strategy will pave a new avenue for the development of in situ renewable smart hydrogels for real-world applications.

Cow dung-derived biochars engineered as antibacterial agents for bacterial decontamination

Disposal of the pollutants arising from farming cattle and other livestock threatens the environment and public safety in diverse ways. Herein, we report on the synthesis of engineered biochars using cow dung as raw material, and investigating these biochars as antibacterial agents for water decontamination. By coating the biochars with N-halamine polymer and loading them with active chlorine (i.e., Cl⁺), we were able to regulate them on demand by tuning the polymer coating and bleaching conditions. The obtained N-halamine-modified biochars were found to be extremely potent against Escherichia coli and Staphylococcus aureus. We also investigated the possibility of using these N-halamine-modified biochars for bacterial decontamination in real-world applications. Our findings indicated that a homemade filter column packed with N-halamine-modified biochars removed pathogenic bacteria from mining sewage, dairy sewage, domestic sewage, and artificial seawater. This proposed strategy could indicate a new way for utilizing livestock pollutants to create on-demand decontaminants.

Synthesis and Biological Activity Evaluation of Polyfunctionalized Anthraquinonehydrazones

Background :

Anthraquinone derivatives, frequently occurring motifs in many various natural compounds, have attracted a great deal of interest as compounds with a wide spectrum of biological activities.

Introduction:

The hybrid pharmacophore approach has become an object of considerable interest due to the incorporation of a five- or six-membered heterocyclic rings in the structure of various natural compounds, especially anthraquinone derivatives.

Methods:

A series of polyfunctionalized anthraquinonehydrazones have been synthesized via the azo-coupling reaction between anthraquinone-based triazenes and methylene active compounds. The structures of synthesized compounds were confirmed by spectral data. Some of the synthesized compounds were screened for their in vitro anticancer activity according to US NCI protocols. The screening of antimicrobial and antifungal activities against Candida albicans and Lactobacillus sp. was carried out. The synthesized compounds were evaluated for their antioxidant (DPPH free radical scavenging assay) and herbicidal activity.

Results:

The synthesized 1-[N'-(5-oxo-2-thioxoimidazolidin-4-ylidene)-hydrazino]-anthraquinone 1.5 displayed a high level of antimitotic activity against tested human tumor cells with mean GI50/TGI values 4.06/78.52μM. The screening of antimicrobial and antifungal activities led to the identification of 1.8 and 1.9 with a moderate effect on Candida albicans and Lactobacillus sp. Antioxidant activity evaluation allowed the identification of 1-[N'-(3-methyl-5-oxo-1-phenyl-1,5- dihydropyrazol-4-ylidene)-hydrazino]-anthraquinone 1.8 with an IC50 value of 3.715 mM. The herbicidal activity screening led to compound identification 1.8 with growth inhibition of Agrostis stolonifera at 25 %.

Conclusion:

The obtained anthraquinonehydrazones constitute an interesting template for the design of new synthetic agents with polypharmacological activities.

Highly Antibacterial Efficacy of a Cotton Fabric Treated with Piperazinyl Schiff Base

Due to the structure of hierarchical aligned cellulose fibrils, cotton fabric used in clothing possesses excellent moisture and thermal managements. Such structure yet may retain metabolic excrements and sebum secretions discharged from the human skin, which reproduce microorganisms harmful for human health. However, incorporating the antimicrobial coating into the cotton fabric can sufficiently resist the microorganism growth. In this work, a water-soluble antibacterial coating named N-(4-(allyloxy) benzylidene)-2-(piperazin-1-yl) ethanamine (NABPE) was synthesized to produce a rechargeable and fast sterilization cotton fiber fabric (M-cotton/NABPE). M-cotton/NABPE exhibited a high effective antibacterial activity, and the inhibition ratios against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were 94 % and 93 %, respectively. Chlorination was performed with sodium hypochlorite solution to form N-Cl bond on the M-cotton/NABPE fabrics, resulting in a high biocidal efficacy of up to 100 % via contact killing for a duration of 5 min. After 25 washing cycles, the antibacterial fabric still maintained an antibacterial rate of 91.95 % and 92.15 % against E. coli and S. aureus, respectively. Furthermore, the fabrics showed integrated properties of excellent UV stability, long-term stability, robust rechargeable biocidal activity (chlorine recharging >5000 ppm) and washing durability. This research provides fundamental insights into the synthesis of the NABPE and prolonged biocidal efficacy of the M-cotton/NABPE, and thereby pave a pathway to incorporate an economic and environmental-friendly antibacterial coating suitable for finishing cotton fabric.

Supercritical carbon dioxide application using hydantoin acrylamide for biocidal functionalization of polyester

Biocidal functionalization in polyester fibers is a really tough challenge because of the lack of tethering groups. This study indicated supercritical carbon dioxide application using N-halamine would be an alternative solution for obtaining antibacterial function on the polyester surface. Firstly, N-(2-methyl-1-(4-methyl-2,5-dioxo-imidazolidin-4 yl)propan-2 yl)acrylamide was synthesized and applied to the polyester in supercritical carbon dioxide medium, at 120 °C, 30 MPa for different processing times. The addition of N-halamine on the surface significantly brought antibacterial activity against E. coli. The chlorine loadings showed that 6 -h exposure time was critical to obtain sufficient antibacterial activity. This treatment caused a reasonable and tolerable loss in color and mechanical properties. But, the durability to abrasion, stability, and rechargeability of oxidative chlorine, and the durability of N-halamine on the surface were remarkably good. Conclusively, it can be available to work on polyester surfaces with resource-efficient and eco-friendly supercritical carbon dioxide technique for getting more functionalization and modification.

Anti-inflammatory Cotton Fabrics and Silica Nanoparticles with Potential Topical Medical Applications

The preparation of functional cotton fabrics and silica nanoparticles by direct covalent linking of nonsteroidal anti-inflammatory drugs (salicylic acid, ibuprofen, and diclofenac) through an amide group is reported. Moreover, the coating of cotton fabrics with silica nanoparticles functionalized with such antiinflamatory agents is found to increase the roughness of the surface, providing hydrophobicity to the modified fabrics. This property is enhanced by the addition of fluorinated alkyl silane in the co-condensation process to form the coating solution. Characterization of the functionalized nanoparticles and cotton textiles is accomplished by microscopic and spectroscopic techniques. The treatment of functionalized nanoparticles and cotton fabrics with model proteases and leukocytes from animal origin results in the in situ release of the drug by the selective enzymatic cleavage of the amide bond. Topical cutaneous applications in wound dressings and cream formulations for the acceleration of wound healing are envisaged.

Construction of Antibacterial N-Halamine Polymer Nanomaterials Capable of Bacterial Membrane Disruption for Efficient Anti-Infective Wound Therapy

The increasing occurrence of bacterial infection at the wound sites is a serious global problem, demanding the rapid development of new antibacterial materials for wound dressing to avoid the abuse of antibiotics and thereby antibiotic resistance. In this work, the authors first report on antibacterial N-halamine polymer nanomaterials based on a strategic copolymerization of 3-allyl-5,5-dimethylhydantoin (ADMH) and methyl methacrylate (MMA), which exhibits in vitro and in vivo antimicrobial efficacy against pathogenic bacteria including Staphylococcus aureus and Escherichia coli. Particularly, when a biological evaluation is run for wound therapy, the N-halamine polymer nanomaterials exhibit a powerful antibacterial efficiency and wound healing ability after a series of histological examination of mouse wound. After the evaluation of biological and chemical surroundings, the proposed four-stage mechanism suggests that, with unique antibacterial NCl bonds, the N-halamine polymer nanomaterials can disrupt the bacterial membrane, as a result causing intracellular content leaked out and thereby cell death. Based on the synergistic action of antibacterial and wound therapy, the N-halamine polymer nanomaterials are expected to be promising as wound dressing materials in medical healing and biomaterials.

N-halamine-based multilayers on titanium substrates for antibacterial application

Bacterial infection is one of the most severe postoperative complications leading to clinical orthopedic implants failure. To improve the antibacterial property of titanium (Ti) substrates, a bioactive coating composed of chitosan-1-(hydroxymethyl)- 5,5-dimethylhydantoin (Chi-HDH-Cl) and gelatin (Gel) was fabricated via layer-by-layer (LBL) assembly technique. The results of Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (¹HNMR) and X-ray photoelectron spectroscopy (XPS) showed that Chi-HHD-Cl conjugate was successfully synthesized. Scanning electron microscopy (SEM), atomic force microscope (AFM) and water contact angle measurements were employed to monitor the morphology, roughness changes and surface wettability of Ti substrates, which proved the multilayers coating formation. Antibacterial assay against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) revealed that the Gel/Chi-HDH-Cl modified Ti substrates most efficiently inhibited the adhesion and growth of bacteria. Meanwhile, in vitro cellular tests confirmed that Gel/Chi-HDH-Cl multilayers had no obvious cytotoxicity to osteoblasts. The study thus provides a promising method to fabricate antibacterial Ti-based substrates for potential orthopedic application.

From Nano to Micro: using nanotechnology to combat microorganisms and their multidrug resistance

The spread of antibiotic resistance and increasing prevalence of biofilm-associated infections is driving demand for new means to treat bacterial infection. Nanotechnology provides an innovative platform for addressing this challenge, with potential to manage even infections involving multidrug-resistant (MDR) bacteria. The current review summarizes recent progress over the last 2 years in the field of antibacterial nanodrugs, and describes their unique properties, mode of action and activity against MDR bacteria and biofilms. Biocompatibility and commercialization are also discussed. As opposed to the more common division of nanoparticles (NPs) into organic- and inorganic-based materials, this review classifies NPs into two functional categories. The first includes NPs exhibiting intrinsic antibacterial properties and the second is devoted to NPs serving as a cargo for delivering antibacterial agents. Antibacterial nanomaterials used to decorate medical devices and implants are reviewed here as well.

Controlling bacterial fouling with polyurethane/N-halamine semi-interpenetrating polymer networks

N -halamine-based interpenetrating polymer networks were developed as a simple and effective strategy in the preparation of antimicrobial polymers. An N-halamine monomer, N-chloro-2, 2, 6, 6-tetramethyl-4-piperidyl methacrylate, was incorporated into polyurethane in the presence of a cross-linker and an initiator. Post-polymerization of the monomers led to the formation of polyurethane/N-halamine semi-interpenetrating polymer networks. The presence of N-halamines in the semi-interpenetrating polymer networks was confirmed by attenuated total reflectance infrared, water contact angle, and energy-dispersive X-ray spectroscopy analysis. The N-halamine contents in the semi-interpenetrating polymer networks could be readily controlled by changing reaction conditions. The distribution of active chlorines within the semi-interpenetrating polymer networks was characterized with energy-dispersive X-ray spectroscopy. Contact mode antimicrobial tests, zone of inhibition studies, and scanning electron microscopy observations showed that the semi-interpenetrating polymer networks had potent antimicrobial and antifouling effects against both Gram-positive and Gram-negative bacteria. Release tests demonstrated the outstanding stability of the N-halamine structures in the new semi-interpenetrating polymer networks.

Chlorine-Resistant Polyamide Reverse Osmosis Membrane with Monitorable and Regenerative Sacrificial Layers

Improving chlorine stability is a high priority for aromatic polyamide (PA) reverse osmosis (RO) membranes especially in long-term desalination. In this Research Article, PA RO membranes of sustainable chlorine resistance was synthesized. Glycylglycine (Gly) was grafted onto the membrane surface as a regenerative chlorine sacrificial layer, and the zeta-potential was used to monitor the membrane performance and to conduct timely regeneration operations for chlorinated Gly. The Gly-grafted PA membrane exhibited ameliorative chlorine resistance in which the N-H moiety of glycylglycine served as sacrificial pendants against chlorine attacks. Cyclic chlorination experiments, combined with FT-IR and XPS analysis, were carried out to characterize the membrane. Results indicated that the resulting N-halamines could be fast regenerated by a simple alkaline reduction step (pH 10). A synchronous relationship between the zeta-potential and the chlorination extent of the sacrificial layer was observed. This indicated that the zeta-potential can be used as an on-site sensor to conduct a timely regeneration operation. The intrinsic mechanism of the surface sacrificial process was also studied.

N-Halamine-Containing Electrospun Fibers Kill Bacteria via a Contact/Release Co-Determined Antibacterial Pathway

N-Halamine-based antibacterial materials play a significant role in controlling microbial contamination, but their practical applications are limited because of their complicated synthetic process and indistinct antibacterial actions. In this study, novel antibacterial N-halamine-containing polymer fibers were synthesized via an one-step electrospinning of N-halamine-containing polymers without any additives. By adjusting the concentration of precursor and the molecular weight of polymers, the morphology and size of the as-spun N-halamine-containing fibers can be regulated. The as-spun fibers showed antibacterial activity against both Gram-positive and Gram-negative bacteria. After an antibacterial assessment using different biochemical techniques, a combined mechanism of contact/release co-determined killing action was evidenced for the as-spun N-halamine-containing fibers. With the aid of contact action and/or release action, this combined mechanism can allow N-halamines to attack bacteria, making the as-spun fibers wide in the application of antibacterial fields, whatever it is in dry or wet environment. Also, a recycle antibacterial test demonstrated that the as-spun fibers can still offer antibacterial property after five recycle experiments.

Facile synthesis of N-halamine-labeled silica-polyacrylamide multilayer core-shell nanoparticles for antibacterial ability

Silica-polymer antimicrobial composites with a core-shell nanostructure are often prepared through a polymeric process. However, it is difficult to control the polymerization degree of the polymers to give a uniform size distribution. In this article, we present a facile approach to produce antimicrobial silica@polyacrylamide (SiO₂@PAM) core-shell nanoparticles, which were synthesized via an electrostatic self-assembly method using acyclic N-halamine polymeric polyacrylamide. The morphologies and structures of these as-prepared nanoparticles were characterized by different techniques. And their antibacterial performance against both Gram-positive bacteria and Gram-negative bacteria was also evaluated. Based on the preliminary results, these core-shell nanosized spheres were made of an outer polymer shell which decorated the inner SiO₂ core, showing the encapsulation of silica nanoparticles with PAM polymers. After chlorination, the resultant nanosized particles displayed a powerful and stable bactericidal capability toward both of the two model bacterial species. Bactericidal assessment further suggested a coordinated effect of the well-known antibacterial performance of N-halamines and the flocculation of PAM on the antibacterial behavior. The in vitro cytotoxicity of the prepared nanoparticles with varying concentrations was studied using mouse fibroblast cells (L929). The CCK-8 assay revealed that the SiO₂@PAM composites possessed a non-cytotoxic and favorable response to the seeded cells in vitro. These results indicate the suitability of the SiO₂@PAM composite particles for controlling biocidal activity, demonstrating their potential applications in deactivating bacteria or even disease control.

Resinas poliméricas reticuladas com ação biocida: atual estado da arte

ResumoCopolímeros reticulados à base de divinilbenzeno vêm sendo extensivamente empregados como suportes de catalisadores e complexantes de íons metálicos, adsorventes de compostos orgânicos e fases estacionárias em separações cromatográficas. A introdução de grupos biocidas a estes materiais é relatada em patentes desde a década de 1970, contudo apenas a partir do ano 2000 estes copolímeros passaram a ser aplicados também como suportes para grupos biocidas. A presente revisão apresenta as principais combinações de suportes poliméricos e grupos biocidas estudados com o objetivo de preparar resinas biocidas reticuladas. Procura-se estabelecer relação entre as características dessas resinas e seu mecanismo de ação biocida.

Synthesis and bactericidal evaluation of imide N-halamine-loaded PMMA nanoparticles

Antibacterial imide N-halamine-loaded PMMA nanoparticles were fabricated, and their bactericidal activities were systematically evaluated.

Enhancement in membrane performances of a commercial polyamide reverse osmosis membrane via surface coating of polydopamine followed by the grafting of polyethylenimine

A commercial aromatic polyamide RO membrane was modified via surface coating of polydopamine followed by the grafting of polyethylenimine. The modification enhanced the chlorine resistance, anti-fouling and antibacterial properties of the membrane.

Design, synthesis and biocidal effect of novel amine N-halamine microspheres based on 2,2,6,6-tetramethyl-4-piperidinol as promising antibacterial agents

Novel superior antibiotics, i.e. amine N-halamine nanoparticles were synthesized via the radical copolymerization, and their bactericidal effects were studied.

Chalcone coating on cotton cloth – an approach to reduce attachment of live microbes

Cloths coated with 4-sulfonylmethyl chalcone prevented the growth of Gram positive and Gram negative microorganisms.

Synthesis and biocidal activity of novel N-halamine hydantoin-containing polystyrenes

Three homopolymers containing hydantoin substituents were obtained by chemical modification of reactive p-chloromethylated polystyrene. The prepared polymers were chlorinated to yield N-halamine materials with biocidal properties. The chemical structure of polymers was characterized by Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. All of the hydantoin polymers are insoluble in water and common organic solvents. Microbiological investigations prove the high biocidal activity of the obtained chlorinated polystyrene derivatives containing spirohydantoin moieties. The obtained polymers will be useful in designing and constructing medical and pharmaceutical equipment. The ability to crosslink allows to expect easy grafting of these biocidal macrochains, for example, on textiles.

Barbituric acid-based magnetic N-halamine nanoparticles as recyclable antibacterial agents

Novel recyclable bactericidal materials, barbituric acid-based magnetic N-halamine nanoparticles (BAMNH NPs), were fabricated by coating of magnetic silica nanoparticles (MS NPs) with barbituric acid-based N-halamine by the aid of the radical polymerization. The sterilizing effect on the bacterial strain is investigated by incubating Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis). The as-prepared BAMNH NPs exhibit higher biocidal activity than the bulk powder barbituric acid-based N-halamine due to the high activated surface area. The structural effect of N-halamine on antimicrobial performance was fully clarified through the comparison between BAMNH NPs and hydantoin-based magnetic N-halamine nanoparticles (HMNH NPs). BAMNH NPs exhibited promising stability toward repeated washing and long-term storage. BAMNH NPs with different chlorine content were comparatively chosen to investigate the influence of chlorine content on the antimicrobial activity. An antibacterial recycle experiment revealed that no significant change occurred in the structure and antibacterial efficiency of BAMNH NPs after five recycle experiments. The combination of barbituric acid-based N-halamine with magnetic component results in an obvious synergistic effect and facilitates the repeated antibacterial applications, providing potential and ideal candidates for sterilization or even for the control of disease.

A review of the biomaterials technologies for infection-resistant surfaces

Anti-infective biomaterials need to be tailored according to the specific clinical application. All their properties have to be tuned to achieve the best anti-infective performance together with safe biocompatibility and appropriate tissue interactions. Innovative technologies are developing new biomaterials and surfaces endowed with anti-infective properties, relying either on antifouling, or bactericidal, or antibiofilm activities. This review aims at thoroughly surveying the numerous classes of antibacterial biomaterials and the underlying strategies behind them. Bacteria repelling and antiadhesive surfaces, materials with intrinsic antibacterial properties, antibacterial coatings, nanostructured materials, and molecules interfering with bacterial biofilm are considered. Among the new strategies, the use of phages or of antisense peptide nucleic acids are discussed, as well as the possibility to modulate the local immune response by active cytokines. Overall, there is a wealth of technical solutions to contrast the establishment of an implant infection. Many of them exhibit a great potential in preclinical models. The lack of well-structured prospective multicenter clinical trials hinders the achievement of conclusive data on the efficacy and comparative performance of anti-infective biomaterials.

Recyclable and stable silver deposited magnetic nanoparticles with poly (vinyl pyrrolidone)-catechol coated iron oxide for antimicrobial activity

This paper introduces a facile method to make highly stable and recyclable antimicrobial magnetic nanoparticles (NPs). Initially, magnetic iron oxide nanoparticles (IONPs) were coated with poly (vinyl pyrrolidone) conjugated catechol (PVP-CCDP). Afterward, silver nanoparticles (Ag(0)) were deposited onto PVP-CCDP coated IONPs using remain catechol. The prepared nanoparticles showed long term (~4 weeks) colloidal stability and redispersibility, respectively, against external magnetic field and over a broad range of pH (4-12). The NPs were characterized by UV-vis, SEM, XPS, and XRD measurements. TEM and DLS analyses showed that the mean particle size of PVP-CCDP coated IONPs/Ag(0) were about 72 nm. The recyclable magnetic NPs possessed a high antibacterial effect against the model microbes Staphylococcus aureus and Escherichia coli and could be separated easily using magnet following antibacterial test for repeated uses and maintained 100% antibacterial efficiency during three cycles. In MTT assay, the magnetic nanoparticles possessed no measureable cytotoxicity to live cells.

Antimicrobial N-halamine polymers and coatings: a review of their synthesis, characterization, and applications

Antimicrobial N-halamine polymers and coatings have been studied extensively over the past decade thanks to their numerous qualities such as effectiveness toward a broad spectrum of microorganisms, long-term stability, regenerability, safety to humans and environment and low cost. In this review, recent developments are described by emphasizing the synthesis of polymers and/or coatings having N-halamine moieties. Actually, three main approaches of preparation are given in detail: polymerization, generation by electrochemical route with proteins as monomers and grafting with precursor monomers. Identification and characterization of the formation of the N-halamine bonds (>N-X with X = Cl or Br or I) by physical techniques such as Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), and by chemical reactions are described. In order to check the antimicrobial activity of the N-halamine compounds, bacterial tests are also described. Finally, some examples of application of these N-halamines in the water treatment, paints, healthcare equipment, and textile industries are presented and discussed.

Modifying Fe3O4-functionalized nanoparticles with N-halamine and their magnetic/antibacterial properties

Magnetic/antibacterial bifunctional nanoparticles were fabricated through the immobilization of antibacterial N-halamine on silica-coated Fe(3)O(4)-decorated poly(styrene-co-acrylate acid) (PSA) nanoparticles. The samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS), X-ray diffraction (XRD), energy-dispersive X-ray spectrometry (EDX), Fourier transform infrared (FTIR), and thermogravimetric analysis (TGA). The N-halamine was developed from the precursor 5,5-dimethylhydantoin (DMH) by chlorination treatment, and experimental results showed that the loading amount of DMH on the silica-coated Fe(3)O(4)-decorated poly(styrene-co-acrylate acid) nanoparticles was adjustable. The as-synthesized nanoparticles exhibited superparamagnetic behavior and had a saturation magnetization of 18.93 emu g(-1). Antibacterial tests showed that the resultant nanoparticles displayed enhanced antibacterial activity against both Gram-positive and Gram-negative bacteria compared with their bulk counterparts.

N-halamine biocidal coatings via a layer-by-layer assembly technique

Two N-halamine copolymer precursors, poly(2,2,6,6-tetramethyl-4-piperidyl methacrylate-co-acrylic acid potassium salt) and poly(2,2,6,6-tetramethyl-4-piperidyl methacrylate-co-trimethyl-2-methacryloxyethylammonium chloride) have been synthesized and successfully coated onto cotton fabric via a layer-by-layer (LbL) assembly technique. A multilayer thin film was deposited onto the fiber surfaces by alternative exposure to polyelectrolyte solutions. The coating was rendered biocidal by a dilute household bleach treatment. The biocidal efficacies of tested swatches composed of treated fibers were evaluated against Staphylococcus aureus and Escherichia coli. It was determined that chlorinated samples inactivated both S. aureus and E. coli O157:H7 within 15 min of contact time, whereas the unchlorinated control samples did not exhibit significant biocidal activities. Stabilities of the coatings toward washing and ultraviolet light exposure have also been studied. It was found that the stability toward washing was superior, whereas the UVA light stability was moderate compared to previously studied N-halamine moieties. The layer-by-layer assembly technique can be used to attach N-halamine precursor polymers onto cellulose surfaces without using covalently bonding tethering groups which limit the structure designs. In addition, ionic precursors are very soluble in water, thus promising for biocidal coatings without the use of organic solvents.

Acyclic N-Halamine Polymeric Biocidal Films

Low concentrations of acyclic amide monomers, methacrylamide (MAM) and acrylamide (AM), were copolymerized with vinyl acetate (VAc). No significant differences between the synthesized copolymers and poly(VAc) were seen by 1H-NMR, FTIR, and DSC analysis. Biocidal films, formed by coating the copolymers onto polyester transparency slides and polyester fabric swatches, were chlorinated by exposure to sodium hypochlorite solutions. Both S. aureus and E. coli O157: H7 were completely inactivated within 1 min on the transparency slides and polyester fabric swatches derived from poly(VAc-co-MAM). The chlorine on the films was stable under UVA irradiation and the surfaces were rechargeable upon chlorine loss.